The present invention relates to hermetic terminal assemblies and more particularly to an improved hermetic terminal pin and a method and apparatus for making the same.
It is known in the art of hermetic terminal assemblies to employ a current carrying terminal pin with a stop flange and a straight shank, each pin being surrounded by a sleeve and sealed in place within a lip defining a hole in the terminal body by means of a fusible material such as glass. Various arrangements of such hermetic terminal assemblies can be found in U.S. Pat. No. 4,296,275, issued to Benjamin Bowsky on Oct. 20, 1981, and U.S. Pat. No. 4,461,925, issued to Benjamin Bowsky and Glenn A. Honkomp on July 24, 1984.
In the past, the stop flanges for these current carrying terminal pins have been formed through what often has been referred to as a "cold heading" process wherein a pin blank is pressed between a reciprocable press and a base die, a flange forming recess being provided between the press and die so that the pressed pin blank assumes the flange form determined by the recess between the press and die. To provide a fuse-like area in the pin blank, a second metal working rolling step has been employed to roll a groove into the blank adjacent the "cold headed" flange. This past multi-step process has been comparatively expensive and of low productivity, the strength and current carrying properties of the pin sometimes being restricted by axial and lineal stresses and metal crystallization brought on by the cold heading and subsequent groove rolling steps.
The present invention recognizing these problems in the past methods of forming terminal pins provides a unique method and apparatus for forming terminal pins which have improved, uniform current carrying qualities, the novel method and apparatus therefor insuring substantially uniform metal density and consistently high quality current carrying terminal pins, permitting high productivity of these pins at comparatively low cost and with increased material savings. In addition, the resulting terminal pin has increased strength in the flange and flank portions where the same is desired and, at the same time, is provided with a preselected fuse-like area which accommodates for possible malfunctions in other parts of the assembly or the general apparatus with which the assembly is associated. Further, the novel method and apparatus of the present invention permits the ready use of preselected alloys, allowing for reduced forming operations and for controlled metal flow and displacement during such reduced forming operations to reduce metal waste, insure substantial uniform metal density, and improve consistent pin performance quality.
Various other features of the present invention will become obvious to one skilled in the art upon reading the disclosure set forth herein.